At first glance the supermarket off Avenida Francisco Miranda appeared to be a gourmet dream. Smoked salmon in the freezer. An aisle filled with Italian olive oil, balsamic vinegar and pesto. Another aisle stacked with Perrier, champagne and the finest Scotch.

But of milk, eggs, sugar and cooking oil there was no sign. Where were they? The question yesterday prompted a puzzled look from the manager. "There isn't any. Everybody knows that. Pasta is probably the next to go," he shrugged.

Welcome to Venezuela, a booming economy with a difference. Food shortages are plaguing the country at the same time that oil revenues are driving a spending splurge on imported luxury goods, prompting criticism of President Hugo Chávez's socialist policies.

Milk has all but vanished from shops. Distraught mothers ask how they are supposed to feed their infants. Many cafes and restaurants serve only black coffee.

Families say eggs and sugar are also a memory. "The last time I had them was September," said Marisol Perez, 51, a housewife in Petare, a sprawling barrio in eastern Caracas.

When supplies do arrive long queues form instantly. Purchases are rationed and hands are stamped to prevent cheating. The sight of a milk truck reportedly prompted a near-riot last week.

Up to a quarter of staple food supplies have been disrupted, according to Datanalisis, a public opinion and economic research group. To Chávez's detractors the scarcity is evidence that his revolutionary "21st century socialism" is driving South America's oil power towards ruin.

Government price controls on staple foods are so low that producers cannot make a profit, they say, and farms and businesses hesitate to invest in crops or machinery, or stockpile inventories, for fear of expropriations.

"We've warned about this from the beginning - all of these price controls in the long run end up producing shortages," Ismael Perez, of the industry group Conindustria, told Reuters.

The government says that shortages are exaggerated by the media and that they reflect greater spending power by the poor thanks to social programmes which have directed oil revenues into the slums .

Some 10,000 tonnes of imported milk will alleviate scarcity by Christmas and government-funded socialist cooperatives will boost domestic production in the long term, say officials.

Despite the problems Chávez remains popular and is expected to win a referendum next month which will abolish term limits, enabling him to stand for continuous re-election and fulfil his wish to stay in power until 2021 or even 2030. Some analysts warn that populist policies are aggravating the "oil curse" which floods oil producers with cash and makes it cheaper to import goods than to make them.

Well-connected people who can exploit the black market are fuelling a boom not only in luxury food and drink but also cars and holidays. Chávez has railed against the soaring imports of Scotch and Hummers, saying they undermined the effort to create a socialist "new man".